Plant Sanitation. 



178 



v 



do not iujure the cacao itself, and, though I should be sorry to assert that they 

 will never attack Para rubber, what little evidence is available goes to show that 

 they do not relish the foliage of this plant. Moreover, the habits of this particular 

 locust render it specially amenable to treatment. I have shown, in my circular 

 on the " Spotted Locust " (R.B.G. Circulars, Series I, No. 9), how the insects con- 

 gregate in enormous numbers on limited areas where they await their turn to 

 deposit their eggs. All that is required is to mark down these breeding grounds, 

 collect and destroy the breeding locusts, and then fork up the soil with quick -lime. 

 If any real good is to be done, concerted action is necessary, and, in this case, the 

 treatment is so simple and inexpensive that there is no excuse for neglecting it. 

 It will be necessary, on the first appearance of the fully-grown (winged) locusts, to 

 put on a few smart boys to go over the whole estate and locate the breeding places. 

 In districts where there are native holdings, search must be made in them also. As 

 far as my experience goes, the locusts always breed in shady spots, so that patnas 

 and low chena will not require attention. MacDougall's insecticide solution has 

 been found effective as a spray for killing the young locusts ; but by treating the 

 pest as suggested above, it ought to be possible to prevent any hordes of these 

 young hoppers. 



The Superintendent of the Government Stock Garden sends me specimens of 

 a cricket (l/ryllus sp.) which is said to be injuring croquet lawns in Colombo. The 

 Sinhalese name for the insect is said to be ' Polangetia.' The burrows of these 

 crickets are usually very conspicuous by reason of the small heap of sand excavated 

 and left beside the entrance. The insects may be killed by pouring dilute Phenyle 

 or Jeyes' Fluid into the holes. If too numerous to make this plan practicable 

 poisoned baits should be sprinkled over the grass. The mixture recommended for 

 destruction of locusts (vide Tropical Agriculturist, November, 1905, pp. 628-9) should 

 prove effective. Another useful bait is the ' bran-arsenic-mash ' which is com- 

 pounded of 1 lb. arsenic or Paris Green with ft to 10 lb. of bran and enough water 

 to thoroughly moisten the mass. Sugar may be added pound for pound with 

 the arsenic, and is said to add to the attractiveness of the bait. It will be advisable 

 to keep fowls away from the lawns Avhile the poison is in use. 



Specimens of the large Cockchafer (Lepidiota pinguis) have been received 

 from the Gampola district, where they were reported to be defoliating "Dadap"' 

 (Erythrinu) seedlings in a nursery. The beetles being large and conspicious, can 

 be readily collected and destroyed. If necessary, the young plants could be 

 protected by spraying with Paris Green. This insect was described and figured 

 in the Tropical Agriculturist for October, 1905, p. 520. 



The "Lantana Bug" (Orthezia insignia) is a pest that is always with us 

 and one that is difficult or impossible to eradicate. Accidentally introduced in 

 the year 1893, it has, in the ensuing twelve years, followed its principle food 

 plant (the Lantana) all over the Island. If only confined to that weed, its 

 presence might be ignored; but it has unfortunately cultivated a taste for 

 various garden shrubs and plants— such as the Duranta (so largely utilized for 

 hedging), Coleus, Thunbergia, Ipomoea and numerous other favourite garden 

 flowers— which has rendered it most obnoxious to horticulturists. Happily, this 

 pest has as yet shown no marked liking for any of our staple products, though 

 there have been a few instauces of partial infestation of tea. As an introduced 

 insect, it arrived without its natural enemies, and, in spite of its lengthy sojourn 

 with us, appears to be still immune. Spraying with MacDougall's Insecticide 

 will kill the insects, but fresh infestation (probably from a few escapees) soon 

 occurs. In the case of annuals it is best to pull up and burn the infested plants. 

 Shrubs should be heavily pruned, the primings burned, and the remnant sprayed 

 and resprayod at the earliest reappearance of the pest. This same treatment 



